Mercedes-Benz S500 Inteligent Drive TecDay Autonomous Mobility Sunnyvale 2014

Mercedes-Benz S500 Intelligent Drive: Review

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Autonomous vehicles are the future and they're already here.
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Normally when you’re kicking back in a prestige limo, there’s a well-dressed, professional chauffeur up front in the driver’s seat. That's definitely not the case if the vehicle in question is the Mercedes-Benz S500 Intelligent Drive.

Unlike the conventional S-Class 'Benz, the S500 Intelligent Drive doesn’t require anyone to steer the car; it’s all down to a bewildering combination of algorithms, cameras and radar.

We’ve just arrived at the Mercedes-Benz Research and Development North American facility in Sunnyvale, California, to experience first hand what it’s like to be a passenger in one of the world’s first autonomous cars.

It’s a lot more than a mere glimpse into the future of personalised transport, mainly because, well… the future is already here, and its using today’s near-production-standard technology.

And it’s not like we’re using a Mercedes-Benz purpose-built test centre for this particular self-driving vehicle test, either. We’ll be travelling over a 20-kilometre loop on public roads in a real-life environment around Sunnyvale, complete with all the usual obstacles including traffic lights, lane merging and four-way intersections; each with its own stop sign, just to make things more interesting.

Mercedes Benz already completed a significant autonomous vehicle test in Germany in August 2013, when the S500 Intelligent Drive covered the 100km distance between the German cities of Mannheim and Pforzheim. That test followed the historic route used by Bertha Benz in her Patent Wagon 3 motorised vehicle.

The driving environment in the United States presents some unique challenges with autonomous testing compared to the motoring landscape in Germany where the lanes are narrow and limited to three.

In the US, lanes are typically wider and roads can include up to eight lanes in each direction. Traffic signals are on the opposite side of the road, as well as a range of freeway-merging scenarios that the self-drive S-Class has to deal with.

Mercedes-Benz has been testing autonomously driven cars on public roads in the US state of California since mid-September, after it was granted an official licence by the state.

However, in the interests of public safety, the Department of Motor Vehicles (DMV) in California requires specially trained drivers to carry out the autonomous test drives in case it all goes wrong. They must recognise when the car is in autonomous driving mode and must be able to override the system at any time. Furthermore, the car must be capable of stopping autonomously at any time.

To that end, The S500 Intelligent Drive is specially equipped with digital mapping that lists the locations of all 14 traffic lights on the test drive route. It’s also equipped with a veritable arsenal of detection devices including three long-range radars and four short-range radars to improve real-time sensing of other road users and the general surroundings.

There’s also a colour stereo unit installed behind the windscreen, so the S500 not only knows that a traffic signal is coming up, it knows exactly where it is located.

While filming inside the car by a third party is prohibited, as a passenger in the back seat of the Intelligent Drive Benz, I can tell you the system is flat-out mind-blowing.

As the S500 approached the first traffic light, the camera momentarily analysed the status of the traffic light in real time by using colour recognition. That status of the traffic light and the distance to it are displayed in the instrument cluster. If the light is yellow or red, the car brakes and moves off accordingly when the light changes to green – all without the test drivers lifting a finger.

The real test though, is coming up.

As the S500 Intelligent Drive approaches an intersection, it uses both radar sensors and cameras to essentially case the surroundings – this is where it really gets interesting. It detects approaching vehicles and reacts autonomously and according to the right-of-way rules for that particular junction.

If the sensors compute that the other cars are stopping, the system activates the turn indicator and turns autonomously. But if the other vehicles have the right of way, it waits for a safe gap before moving off.

Pedestrian crossings are also marked on the map and as a result, the test car drives slower before a crossing and automatically stops if someone is waiting to cross.

Multi-lane freeways were no problem either, with the S500 capable of registering other road users and infrastructure simultaneously.

The system can pinpoint their precise locations and measure their speeds with a scanning range of up to 192 metres at more than 25 times per second. And just like our lane merging experience, the car simply drives around parked vehicles while following the traffic rules where it is safe to do so, or brakes to a full stop if there are no gaps to safely merge.

However, it’s not perfect. Although the cameras are able to read the lane markings, some slightly nervous lane correcting usually follows right or left-hand turns across an intersection – then it seems to settle down.

Perhaps a more worrying moment for a colleague and I was a full-panic stop on a motorway entrance slip road, as we attempted to merge with another vehicle. Apparently, the system calculated that our car couldn’t safely accelerate past the other car and rather than risk a collision, decided the best course of action was to enact a full stop before continuing onto the freeway with clear space ahead.

Another difficult situation for the Intelligent Drive car to deal with in the Unites States is the four-way stop junctions, which operate on a first-to-arrive, first-to-go basis. While the research car can actually deal with this event successfully, it’s also under continued development along with more up-to-date mapping data that can incorporate up to the minute road changes that local councils might make from day-to-day.

While the Mercedes-Benz S500 Intelligent Drive is no less than science fiction for the here and now, our test drive clearly demonstrated that we are still a long way off the idea that you could walk into a dealership and purchase an autonomous vehicle.

However, with traffic congestion eating up between four and six hours a day in some cities, the idea behind sitting back and either answering emails or just watching the morning news on a big screen TV makes a whole lot of sense.

Stretch the idea further and we can see an app that not only drops you off at work, but is also able to make its way back to your office to collect you at the end of the day.

The possibilities are endless and Mercedes-Benz is at the pointy end of the research.